In a face authentication system as being a system for a personal authentication, a technique to detect a masquerade that uses a photograph or the like has been considered.
For example, a personal authentication device described in Patent Document 1 excludes a masquerade depending on a degree of similarity of facial images under different illumination environments created by changing the illumination environment using an illumination lamp. Also, a masquerade detection device described in Patent Document I excludes a masquerade by comparing distance information obtained by using a distance detection device with face depth information stored in advance. Further, the masquerade detection device described in Patent Document 1 excludes a masquerade by: obtaining various images in which a user's face is picked up from many angles: and authenticating the user's action by using a contributing ratio in the degree of the variation of images obtained by principal component analysis.
A biometric collation device described in Patent Document 2 eliminates a masquerade that uses a photograph by: generating three-dimensional information of a user by using a plurality of picked up images of the user and picked up angles therewith; and collating the information with a three-dimensional shape of a face of an authenticated person stored in advance.
Patent Document 1: Japanese Unexamined Patent Publication 2003-178306
Patent Document 2: Japanese Unexamined Patent Publication 2004-362079